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Ground Faults & Arc Faults

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Module 4 · Ground Faults & Arc Faults

Module 4: Ground Faults & Arc Faults

Training Module #4 — Ground Faults & Arc Faults

Module 4 · Ground Faults & Arc Faults

What are Ground Faults?

Diagram of a ground fault showing a transformer, main service, and equipment, with the unintended electrical path to grounded metal parts highlighted. — A ground fault is contact between a live conductor and a grounded surface.

An unintended path to ground can damage equipment and harm people who touch energized items.

Module 4 · Ground Faults & Arc Faults

Terms and Components

PV wiring diagram showing PV modules, PV disconnect, isolated inverter, the Equipment Grounding Conductor, and the grounding electrode. — EGC, GEC, and grounding electrode in a PV grounding system.

EGC carries ground-fault current and bonds metal parts; GEC connects the system to the grounding electrode.

Module 4 · Ground Faults & Arc Faults

Ground Faults & Arc Faults

PV array on a roof with a small flame on the panels, illustrating how an undetected ground fault can start a fire. — An undetected ground fault can lead to high currents and a fire.

GFP devices have a 'blind spot' below about 1 amp; a second fault can melt insulation and start a fire.

Module 4 · Ground Faults & Arc Faults

Circuit Breakers or Fuses

Ground fault wiring diagram showing a transformer, main service, and equipment, used to illustrate where breakers and fuses protect the circuit. — Breakers and fuses trip before high current melts wire insulation.

A breaker trips before current overheats the wire; tripping on high current can signal a short circuit or ground fault.

Module 4 · Ground Faults & Arc Faults

Causes of Ground Faults

Rows of burned and damaged ground-mounted PV panels and wiring after a fault. — Damaged insulation, bad installs, pinched wires, and water can cause ground faults.

Common causes: damaged insulation, poor installation, pinched wires, and water.

Module 4 · Ground Faults & Arc Faults

Ground fault cause: pinched wires

Diagram of a copper conductor with pinched insulation between grounded metal, lowering the insulation and voltage threshold. — Pinched insulation lets power leak from the copper conductor to grounded metal.

Pinched wires weaken insulation and allow power leakage.

Module 4 · Ground Faults & Arc Faults

Ground fault cause: damaged wire insulation

Photo of damaged cables with stripped and exposed wire insulation lying on the ground. — Damaged or stripped insulation can lead to a short circuit.

Exposed conductors can overheat, melt insulation, and cause a fire.

Module 4 · Ground Faults & Arc Faults

Ground fault cause: water

Photo of an open combiner box on a solar array with wiring inside. — Water entering a combiner box can create a short circuit.

Water is a conductor and carries current to grounded parts.

Module 4 · Ground Faults & Arc Faults

Ground fault cause: rodents

Photo of a squirrel beside a photo of wires with chewed and damaged insulation. — Rodents chew insulation and leave conductors exposed.

An exposed conductor touching metal can arc and cause a fire.

Module 4 · Ground Faults & Arc Faults

Ground fault cause: improper installation

Photo of terminal blocks inside an enclosure with multiple wires connected. — Cross polarity wiring can create a ground fault.

Cross polarity: positive connected to negative, or negative to positive.

Module 4 · Ground Faults & Arc Faults

Poor connections at termination points

Three photos of wire terminations, one showing arcing sparks at a loose terminal connection. — Loose connections cause arcing at termination points.

Wires must be seated correctly in terminals to prevent arcing.

Module 4 · Ground Faults & Arc Faults

Ground Faults: Series and Parallel

A ground fault is current leaking to ground through a damaged conductor.

Module 4 · Ground Faults & Arc Faults

What is an Arc Fault or Flash

An arc can exceed 10,000 degrees Fahrenheit and ignite nearby materials.

Module 4 · Ground Faults & Arc Faults

Finding and Diagnosing Ground Faults

Measure resistance, continuity, and voltage to find ground faults; this needs training.

Module 4 · Ground Faults & Arc Faults

Thanks and Questions

Thanks! Questions? Email asenia@jazzsolar.com or jon@jazzsolar.com.